Until recently, there have been only two basic types of multi-shed weaving systems. One system is the flat weft-wave weaving system wherein a multiplicity of sheds move in the weft direction along a flat path. The second system is the curved warp-wave or rotor system in which a multiplicity of sheds move in the warp direction along a curved path. As is well known to those skilled in the art, both of these weaving systems suffer from several disadvantages, one of the most critical disadvantages being the severe limitation in the diversification of weaves available due to the inability to use standard shed-forming mechanisms.
There is disclosed a third type of multi-shed weaving in applicant's own U.S. Pat. No. 4,122,871 which overcomes many of the disadvantages of the flat weft-wave systems and the curved warp-wave systems. This new and improved multi-shed weaving technique involves the use of flat warp-wave systems (i.e., those in which a multiplicity of sheds move in the warp direction along a substantially flat path). This third type of weaving is advantageous due to its versatility in weaving different patterns while still providing the productivity of multi-shed weft insertion.
In a multi-shed warp-wave loom utilizing applicant's previously disclosed warp-wave weaving system, multiple shed retainers are employed which sustain multiple sheds traveling in a wave-like form in a direction parallel with the warp threads towards the fell of the cloth. Each of the sheds receives a weft thread, which is preferably inserted by an air jet. A separate shed forming apparatus is provided for forming the warp sheds by elevating and lowering selected warp threads in a conventional manner.
The multi-shed weaving systems utilize the fluid jet, usually air, to insert the weft thread through the open sheds, and the fluid, along with the weft thread, are directed through a weft guide channel and shed retainer positioned within the open warp shed. The weft guiding channel is necessary to direct the jet of air within the open shed, and to maintain the speed of the jet at the velocity required for transporting the weft thread completely through the open shed while preventing (1) the jet from interfering with the warp threads forming the open shed and (2) the warp sheds from interfering with the insertion of the weft. Reference is now made to applicant's own U.S. Pat. No. 4,425,946 for a complete and detailed description of such multi-shed weaving systems utilizing a fluid jet, preferably air jet, for weft insertion in a multi-shed warp-wave loom.
As can be appreciated with reference to the multi-shed warp-wave apparatus and method disclosed in applicant's U.S. Pat. No. 4,425,946, a complicated structure is provided for maintaining alignment of the main air nozzles with the moving shed retainers. Specifically, at column 10, there is disclosed a weft insertion mechanism including a plurality of air jets associated with the shed retainers and which are caused to move with the shed retainers in a synchronized movement by a control mechanism utilizing a plurality of manipulating arms secured to the corresponding plurality of air jets. This multiple air jet weft insertion system has been found to be complex and unwieldy in use.
Also, U.S. Pat. No. 4,425,946 generally discloses, at columns 13-14, an air nozzle relay system to assist in transporting an inserted weft yarn through the channel (or tube) defined by a plurality of the shed-retaining members of the shed retainer. As best seen in FIGS. 31-33 of the drawings, the patent discloses providing compressed air to a valve which slidably receives one end of a hollow stem of a shed retaining member therein. Compressed air is supplied to the interior of the valve through a port which normally does not fluidly communicate with a port in the stem of the shed retaining member unless a cam surface urges the valve upwardly against the force of coil springs until the ports communicate and compressed air flows through the stem of the shed retaining member to the passageway of the channel defined by the plurality of shed retaining members. In this fashion, the compressed air delivered to the channel facilitates the insertion of a weft thread initially inserted by an air jet through the entirety of the length of the channel. The air nozzle relay system generally described in applicant's U.S. Pat. No. 4,425,946 also has been found to be complex and impractical in use.
Thus, applicant has now developed an improved weft insertion mechanism and air nozzle relay mechanism that simplifies and yet vastly improves the functionality of applicant's multi-shed warp-wave weaving method and apparatus as previously best described in applicant's own U.S. Pat. No. 4,425,946.